Method for forming a breast prothesis

ABSTRACT

A method for forming the outer surface of a breast prosthesis is disclosed. A digital, three-dimensional image is formed of a patient&#39;s breast using a computerized scanner. A computer-controlled milling machine utilizes the image to form a solid model of the breast. A sheet of flexible, moldable material having a uniform, precise thickness is then vacuum-formed over the breast model. A hard, two-piece mold is cast from the flexible sheet. A soft, curable material is then either poured or injected between the two pieces of the mold to form the breast prosthesis outer surface. The breast prosthesis outer surface is then turned inside out to form a shape that is a mirror image of the patient&#39;s breast.

BACKGROUND OF THE INVENTION

The present invention relates to a method for forming a breastprosthesis, and in particular to a method for forming a breastprosthesis that has a precisely uniform surface thickness and is shapedto mirror the existing breast when held in a brassiere. To form the moldfor the prosthesis, a plastic sheet is formed into the shape of thenatural breast. Once molds are made using this plastic sheet, the breastprosthesis outer surface may be formed within the molds. This outersurface is then turned inside out to form the outer surface for a breastprosthesis that is the mirror image of the natural breast.

The purpose of the disclosed invention is to create a comfortable,natural-appearing breast prosthesis for a patient that has lost one ofher natural breasts. Typically the natural breast is lost as a result ofa mastectomy procedure, although this invention may be utilizedregardless of the reason the patient requires the prosthesis. A breastprosthesis should ideally mirror the size, shape, and texture of theremaining natural breast as closely as possible. In this way thepatient's goal of appearing to have two natural breasts is most nearlyachieved. Since the breast prosthesis is generally only worn while thepatient is wearing a brassiere or other support garment, the shape ofthe breast prosthesis should mirror the shape of the patient's remainingnatural breast while that breast is supported.

Other methods for forming a breast prosthesis shaped to mirror anexisting natural breast are known in the art. U.S. Pat. No. 2,580,264 toWright, et al. discloses a method of producing a mold for an artificialbreast by turning a mold taken from the existing breast inside out. Inthe Wright, et al. process, a plaster of Paris mold is taken of theexisting breast. A coating of quick-drying liquid latex rubber is thenapplied inside the plaster of Paris mold. When dried, the latex rubberforms a flexible casing that may be removed from the plaster of Parismold. The latex rubber casing is turned inside out to form a mold forthe artificial breast that will be a mirror image of the existingbreast.

U.S. Pat. No. 5,527,359 to Nakamura et al. also discloses a method ofproducing a mold for an artificial breast by turning a mold taken fromthe existing breast inside out. In the Nakamura et al. process, a modelof the existing breast is formed using aluminum foil. The aluminum modelis then filled with plaster to form a positive model of the existingbreast. The positive model is then coated with aluminum foil reinforcedby thin adhesive taping. The aluminum foil/adhesive taping complex isthen turned inside out to form a negative model of the artificialbreast.

Other methods are also known for forming a breast prosthesis in theshape of a breast held in place by a support garment. U.S. Pat. No.4,086,666 to Vaskys et al. discloses a method for forming a breastprosthesis in the shape of a supported breast. In addition to using acast made of the patient's chest while not wearing a brassiere, a castis also made of the patient's chest while wearing a brassiere. Thenegative cast is simply formed over the brassiere itself. A sculptorthen uses the positive cast of the supported breast/brassierecombination to help visualize the appearance of the supported breast.Alternatively, Vaskys et al. discloses that measurements may be made ofthe patient's remaining natural breast while the patient is wearing abrassiere to assist the sculptor in forming a prosthesis in the shape ofa supported breast.

U.S. Pat. No. 4,600,551 to Erb discloses a method for producing a breastprosthesis that is symmetrical to the shape of the remaining naturalbreast while that breast is held in a zero-gravity state. After amolding material is applied to the natural breast, the patient isimmersed in a liquid that is of a density essentially equivalent to thedensity of the natural breast. The mold then cures while the breast issuspended in the liquid. The process thus results in a prosthesis thatdoes not require the artistic interpretation of a sculptor to remove theeffects of gravitational stress. However, Erb discloses that the shapeof the breast in a zero-gravity state does not strictly conform to theshape of the breast while supported in a brassiere.

Erb also discloses a method of forming a breast prosthesis using a moldformed from a breast supported by a half-brassiere. The half-brassiereis taped to the patient's chest wall and a mold material is formed overthe natural breast and brassiere. This approach results in a mold thatreflects not the texture of the natural breast only, but also thetexture of the brassiere and supporting tape, and thus requires the useof a sculptor in forming the prosthesis.

The prior art methods of forming a breast prosthesis each have a numberof disadvantages. First, some of these methods require a human sculptorto form molds for the prosthesis from models. The addition of a sculptorgreatly increases the cost and time required for the production of abreast prosthesis. In addition, a human is inherently incapable ofexactly reproducing the shape of the existing natural breast inmirror-image form to create a precisely accurate mirror-imageprosthesis. Instead, a human must rely on his or her artistic abilities,which inevitably introduces some error into the process.

Another disadvantage of the prior art methods is that the exteriorsurface of the resulting breast prosthesis will not be of uniformthickness. Simply pouring or painting a curable material onto a smoothsurface will result in a cured material that is smooth on only the sidethat is in contact with the smooth surface. The other side of the curedmaterial will inevitably be wavy, resulting in a cured material ofnonuniform thickness. The thickness and consistency of the prosthesissurface is critical for several reasons. First, a material that has thinspots may tend to “balloon” at the thin points, resulting in a misshapenprosthesis. On the other hand, a material that is too thick will resultin a prosthesis that does not feel to the touch like a natural breast.Finally, a prosthesis that has an exterior surface of nonuniformthickness will not be as nearly symmetrical with the remaining naturalbreast as would otherwise be possible using a consistently flat exteriorsurface material.

Still another disadvantage of the prior art methods for forming a breastprosthesis is the inability to form an accurate image of a breast heldin a brassiere or other support garment. This shape is preferred bypatients because the prosthesis will typically be worn only while thepatient is wearing a support garment. Since a natural breast necessarilysags somewhat due to gravity, a prosthesis formed in the shapes of anatural breast will not be symmetrical to the remaining natural breastwhen a support garment is worn. The Erb method of forming a breastprosthesis while the natural breast is suspended in a controlled-densityliquid is awkward, expensive, and would likely cause considerableembarrassment to the patient who must enter this liquid while her upperbody is exposed. Moreover, the Erb disclosure indicates that the shapeof a breast in this zero-gravity state does not correspond to the shapeof a breast held in a supported garment, so the resulting prosthesiswould still not mirror the patient's remaining natural breast. The othermethod disclosed by Erb, that of forming a mold over the patient'sremaining natural breast while wearing a half-brassiere, requiresadditional work by an artist to remove the effects of the brassiere onthe mold, which would increase the cost and time required to constructthe prosthesis.

SUMMARY OF THE INVENTION

The present invention is a method for forming a breast prosthesis thatis a mirror image of the remaining natural breast while overcoming thelimitations of prior art methods. The method begins with a computerizedscan of the chest of the patient. This scan is performed while thepatient's natural breast is supported. This computerized scan results ina three-dimensional image file stored on a computer storage medium. Theimage file may be transmitted to a remote facility for the production ofthe prosthetic breast.

At the production facility, the image of the remaining natural breast isemployed by a computer-controlled milling machine to form an image ofthe natural breast. The material from which the breast shape is milledmay be either a hard resin or a softer material. If a soft material isused, it is typically necessary to take an impression of the milledbreast shape which is then cast in a hard resin to form a positive imageof the remaining natural breast.

The positive cast is then placed in a vacuum molding machine where athin sheet of plastic is heated and vacuum formed to the shape of thecast. The plastic sheet is of a precisely measured and consistentthickness. After the vacuum-forming operation is complete, the thinplastic sheet is then in the form of the patient's natural breast.

The plastic sheet is then used to form a two-piece plaster mold. Onepiece of this mold will be a positive model of the patient's naturalbreast; the positive model will fit into the other piece forming anegative model of the patient's breast. A curable material such asSilastic is then injected between the two pieces of the mold to form theouter surface of the breast prosthesis. The Silastic outer surface isthen turned inside out to form the prosthesis outer surface, which willthus have a shape that is the mirror image of the patient's breast. Theresulting breast prosthesis exterior will be of uniform thickness andwill feel to the touch quite similar to a natural breast.

This process results in a number of advantages over the prior artmethods. First, no human sculptor is needed at any stage of thedisclosed method. This removes inaccuracies due to the sculptor'sartistic interpretation, and results in a prosthesis that is a precisemirror image of the patient's natural breast. Moreover, the cost anddelay involved with the use of a sculptor are eliminated.

Another advantage is that the disclosed method allows the production ofa breast prosthesis having a surface with a precisely controlledthickness and uniformity. This eliminates problems with ballooning, andallows the production of a prosthesis that feels to the touch as muchlike a natural breast as possible.

Also, the disclosed method allows the production of a prosthesis thatmirrors the precise shape of the patient's natural breast while held ina support garment. Thus the prosthesis will appear as natural aspossible during the patient's daily activities.

It is therefore an object of the present invention to provide for abreast prosthesis that is the precise mirror image of an existingnatural breast.

It is a further object of the present invention to provide for a breastprosthesis that has an exterior surface of a precise and consistentthickness.

It is also an object of the present invention to provide a breastprosthesis that is in the shape of a natural breast supported by abrassiere or other support garment.

These and other objects and advantages of the present invention will beapparent from a consideration of the following detailed description ofthe preferred embodiments in conjunction with the appended drawings asdescribed following.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a positive model of a patient's naturalbreast produced from a computer-controlled milling machine using athree-dimensional computerized image.

FIG. 2 is a perspective view of a thin plastic sheet that wasvacuum-formed over the positive model of the patient's natural breast.

FIG. 3 is an exploded view of the two-piece mold formed from the plasticsheet.

FIG. 4 is an exploded view of the two-piece mold, as well as theSilastic exterior of the breast prosthesis formed within the two-piecemold.

FIG. 5 is a perspective view of the SILASTIC exterior of the breastprosthesis after it has been turned inside out.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

With reference to FIGS. 1-5, a preferred embodiment of the disclosedinvention may be described. The disclosed method begins with theformation of a three-dimensional image of the patient's breast. Thisimage is created using a scanning device (not shown) as is well known inthe art and has been applied to a myriad of modeling applications.Preferably, the scanning device includes a camera mounted on a supportthat allows the camera to rotate 180° around the object of interest. Theresult of this scanning process is a series of two-dimensional images ofthe object of interest from various angles as the camera moves aroundthe object. Computer software resolves these multiple two-dimensionalimages into a three-dimensional image of the object.

To form a three-dimensional image of the patient's breast, the patientis positioned so that the scanning device's camera will move in an arcaround the patient's breast. The patient is fitted with a supportgarment during the scanning operation so that the resulting prosthesiswill mirror the patient's natural breast while similarly supported;preferably this support garment would be a brassiere that is cut away sothat only half of the cup remains beneath the patient's breast. Athree-dimensional image of the patient's supported breast is then formedfrom the images taken as the camera moves around the patient's breast.Because the support garment only covers the lower portion of thepatient's breast, the resulting image will only be minimally affected bythe presence of the support garment. Any irregularities in the image ofthe patient's breast as a result of the support garment may be smoothedaway using appropriate image-processing software, as is well known inthe art.

The three-dimensional image file is stored on a computer storage medium,such as magnetic disks or a CD-ROM. Since the image file is stored in adigital format, it may be quickly and easily transferred to a remoteproduction facility either by modem or by the shipment of a computerdiskette, CD-ROM, or other electronic storage medium containing theimage file. In addition, this image may be maintained on file so thatshould the patient need an additional or replacement prosthesis moldproduced, the patient will not be required to undergo the scanningprocess again.

At the production facility, the image of the natural breast is employedby a computer-controlled milling machine to cut a three-dimensional formin the shape of the natural breast. The material from which thebreast-shaped form is milled is preferably a hard resin. If a softmaterial is used, it is necessary to take an impression of the milledbreast-shaped form which is then cast in harder material to form apositive image of the breast. In either case, the result of this processis breast positive mold 10, as shown in FIG. 1. Mold base 12 ispreferably formed as an integral support for breast positive mold 10.

Referring now to FIG. 2, plastic sheet 14 is shown. While plastic sheet14 is preferably made of vinyl, any other material, whether plastic orotherwise, may be used, provided such material is sufficiently pliableand moldable to form the necessary shape of the breast prosthesis.Plastic sheet 14 should be of uniform thickness since the thickness ofplastic sheet 14 will be reflected in the thickness of prosthesissurface 20 (shown in FIGS. 5 and 6) as described hereafter. If plasticsheet 14 has thin areas, the resulting prosthesis surface 20 will tendto “balloon” at these thinner points, resulting in a misshapenprosthesis or a rupture of the prosthesis surface 20 due to wear. On theother hand, prosthesis surface 20 must be thin since otherwise it willnot feel to the touch like a natural breast. Experiments have shown thata plastic sheet 14 having a consistent thickness of about 1.9 mmproduces a prosthesis surface 20 that is appropriately thin to simulatethe feel of a natural breast but is still able to withstand everydaywear without damage.

To form plastic sheet 14 into the shape shown in FIG. 2, plastic sheet14 is placed over breast positive mold 10 in a vacuum-forming machine ofconventional design (not shown). Plastic sheet 14 is then heated andvacuum formed such that it forms into the shape of breast positive mold10 as shown in FIG. 2. After the vacuum-forming operation is complete,plastic sheet 14 then forms an exact image of the patient's naturalbreast.

Plastic sheet 14 is next used to form a two-piece plaster mold,consisting of positive prosthesis mold 16 and negative prosthesis mold18, as shown in FIG. 3. Positive prosthesis mold 16 is formed by pouringa hard-curing plaster material into the cup formed by plastic sheet 14and allowing the material to cure. Positive prosthesis mold 16 thusforms a model of the patient's natural breast. Negative prosthesis mold18 is formed by pouring the hard-curing plaster material into acylindrical container (not shown) and then pressing plastic sheet 14into the plaster material while prosthesis mold 16 is still withinplastic sheet 14. Once negative prosthesis mold 18 dries, it will form anegative model of the patient's natural breast, although it will ofcourse be slightly larger than the patient's natural breast due to thethickness of plastic sheet 14.

A soft, curable material is then used to form prosthesis surface 20 asshown in FIG. 4. SILASTIC, a room temperature, vulcanizable siliconeproduct that is widely available and is manufactured by Dow Corning, hasbeen found to be effective for forming prosthesis surface 20. In onemethod of forming prosthesis surface 20, SILASTIC is poured intonegative prosthesis mold 18, and then positive prosthesis mold 16 isplaced within negative prosthesis mold 18. Alternatively, Silastic couldbe injected between positive prosthesis mold 16 and negative prosthesismold 18. The resulting breast prosthesis surface 20 will be of uniformthickness, mimicking the thickness and shape of plastic sheet 14.

Once prosthesis surface 20 is dry, it may be removed from the mold andturned inside out as shown in FIG. 5. Once prosthesis surface 20 isturned inside out, it forms a shape that is the precise mirror image ofthe patient's natural breast. Prosthesis surface 20 can then be trimmedfor a smooth edge by removing flashing 22. To form the completeprosthesis, the prosthesis surface 20 may be filled with a gel material,and a rear portion (not shown) can be attached in a conventional mannerto finish the prosthesis.

In an alternative embodiment of the invention, plastic sheet 14 may beturned inside out before positive prosthesis mold 16 and negativeprosthesis mold 18 are formed. In this embodiment, positive prosthesismold 16 would be a model of the mirror image of the patient's naturalbreast rather than a model of the breast itself. It would be unnecessaryto turn prosthesis surface 20 inside out after it is formed since itwould already be in the shape of the mirror image of the patient'snatural breast.

The present invention has been described with reference to certainpreferred and alternative embodiments which are intended to be exemplaryonly and not limiting to the full scope of the present invention as setforth in the appended claims.

1. A method for forming a breast prosthesis comprising the method stepsof: (a) producing a three-dimensional image of a breast by performing acomputerized scan of the breast; (b) producing a positive model of thebreast based on said three-dimensional image; (c) vacuum-forming auniformly flat flexible sheet having a consistent thickness over saidpositive model such that said flexible sheet is molded into the shape ofsaid positive model thereby forming an interior side and exterior side;(d) casting a two-piece solid mold from said flexible sheet, said twopiece mold comprising a first piece formed over the exterior side ofsaid flexible sheet, and said second piece formed within the interiorside of said flexible sheet; (e) introducing a curable material intosaid mold between said first piece and said second piece to form abreast prosthesis having an inner surface and an outer surface andhaving a consistent thickness; and (f) turning said breast prosthesisinside out such that said inner surface becomes the outer surface ofsaid breast prosthesis to form a precise mirror image of the breast. 2.The method of claim 1, wherein said thickness of said flexible sheet isabout 1.9 millimeters.
 3. The method of claim 2, wherein said flexiblesheet comprises vinyl.
 4. The method of claim 1, wherein the breast isheld in a support garment during step (a).
 5. The method of claim 4,wherein said support garment comprises a half-cup fitted underneath thebreast.
 6. The method of claim 1, wherein said curable material issilicone material.
 7. The method of claim 1, wherein step (a) isperformed using a camera on a 180° mount.
 8. The method of claim 1,wherein step (b) is performed using a computer-controlled millingmachine.
 9. A method of forming a breast prosthesis, comprising: (a)scanning the breast to create two-dimensional images of the breast fromtwo or more angles, wherein the breast is held in a support garmentduring scanning of the breast, the support garment being at leastpartially altered such that an upper portion of the breast is uncoveredfor scanning; (b) using the two-dimensional images of the breast tocreate a three-dimensional image; (c) using the three-dimensional imageof the breast to produce a positive model of the breast; and (d) usingthe positive model to produce a breast prosthesis.
 10. The method ofclaim 9, wherein the breast is scanned by a camera at various angles asthe camera moves around the breast.
 11. The method of claim 9, whereinthe breast is scanned by a camera mounted on a support that allows thecamera to move around the breast.
 12. The method of claim 11, whereinthe support allows the camera to rotate about 180° around the breast.13. The method of claim 11, wherein the support allows the camera tomove in an arc.
 14. The method of claim 9, further comprisingtransmitting the three-dimensional image to a production facility. 15.The method of claim 9, wherein a milling machine is used to perform step(c).
 16. The method of claim 9, further comprising modifying thethree-dimensional image to reduce irregularities in thethree-dimensional image caused by the support garment.
 17. A method forforming a breast prosthesis, comprising: (a) producing athree-dimensional image of a breast by performing a computerized scan ofthe breast; (b) producing a positive model of the breast based on saidthree-dimensional image; (c) vacuum-forming a flexible sheet having aconsistent thickness over said positive model such that said flexiblesheet is molded into the shape of said positive model thereby forming aninterior side and exterior side; (d) casting a two-piece solid mold fromsaid flexible sheet, said two-piece solid mold comprising a first pieceformed over the exterior side of said flexible sheet, and said secondpiece formed within the interior side of said flexible sheet; (e)injecting or pouring a curable material into said mold between saidfirst piece and said second piece to form a breast prosthesis having aninner surface and an outer surface and having a consistent thickness;and (f) turning said breast prosthesis inside out such that said innersurface becomes the outer surface of said breast prosthesis to form amirror image of the breast.
 18. A method of forming a breast prosthesis,comprising: (a) scanning the breast to create at least onetwo-dimensional image of the breast; (b) using one or more of thetwo-dimensional images of the breast to create a three-dimensionalimage; and (c) using the three-dimensional image of the breast toproduce a positive model of the breast; (d) vacuum-forming a flexiblesheet having a consistent thickness over said positive model such thatsaid flexible sheet is molded into the shape of said positive modelthereby forming an interior side and exterior side; (e) casting atwo-piece solid mold from said flexible sheet, said two-piece solid moldcomprising a first piece formed over the exterior side of said flexiblesheet, and said second piece formed within the interior side of saidflexible sheet; and (f) injecting or pouring a curable material intosaid mold between said first piece and said second piece to form abreast prosthesis having an inner surface and an outer surface andhaving a consistent thickness.
 19. The method of claim 18, wherein step(a) is performed using a camera mounted on a support that allows thecamera to move in an arc around the breast.
 20. The method of claim 18,further comprising storing the three-dimensional image on a computerstorage medium.
 21. The method of claim 18, wherein a milling machine isused to performed step (c).
 22. The method of claim 18, wherein thebreast is held in a support garment during step (a).
 23. The method ofclaim 22, further comprising modifying the three-dimensional image toreduce irregularities in the three-dimensional image caused by thesupport garment.
 24. The method of claim 9, wherein the support garmentonly covers the lower portion of the breast.